Childhood Hygienic Practice and Family Education Status Determine the Prevalence of Helicobacter pylori Infection in Iran

Background: Management of Helicobacter pylori , a causative agent of gastrointestinal diseases is an important health problem in most countries. The main reasons include poorly defined epidemiological status and unrecognized mode of bacterial transmission. Our objective was to investigate the prevalence of H. pylori infection in a representative population of Iran and to evaluate possible risk factors for the H. pylori infection.
Materials and methods: In this cross-sectional study, 2561 healthy individuals aged 18–65 years (mean age, 35.5 years) were selected out of 12,100,000 inhabitants of Tehran province by cluster sampling. Infection with H. pylori was evaluated by detection of anti- H. pylori IgG antibody in serum. Sociodemographic status of each subject was determined by filling up a questionnaire.
Results: Prevalence of H. pylori infection was 69% and was correlated with increasing age. The highest infection rate (79.2%) was seen in individuals 46–55 years old. No association was detected between H. pylori positivity and gender. Low education of the study subjects; low father's and mother's education; poor tooth brushing habit; crowded families in childhood; and lack of household bath, hygienic drinking water, and swage disposal facility in childhood were determined as possible risk factors.
Conclusions: The rate of prevalence of H. pylori infection was higher than developed countries. Low socioeconomic status, poor sanitary indications, and crowded families in childhood were related to high prevalence of H. pylori infection in Iran. Accordingly, fecal–oral and oral–oral routes could be considered as the main pathways of transmission of H. pylori .     

Prevalence and risk factors for Helicobacter pylori infection in Chinese populations

Background:  The prevalence of Helicobacter pylori is higher in developing countries. The aim of this study was to investigate the prevalence and risk factors of H. pylori infection in areas with high prevalence of gastric cancer in Jiangsu Province, China.
Methods:  A prospective epidemiologic survey of H. pylori infection was accomplished in a natural population of 1457 individuals in Xiangshui and Gaoyou counties, Jiangsu Province, China. Questionnaires and laboratory tests for H. pylori infection (¹³C-urea breath test and serum IgG antibodies to H. pylori ) were used and performed, respectively.
Result:  Among 1371 subjects who completed questionnaires and H. pylori detection, 851 (62%) were H. pylori positive. The prevalence reached a peak at the age of 30–40 years (67%). There was no sex difference. The annual family income level was shown to be positively correlated with the risk of H. pylori infection. The prevalence of H. pylori infection was also associated with family size, education level, and several diet-related factors, such as the number of times cooked rice and potatoes eaten per week, and a family history of stomach diseases. Compared to nonsymptomatic individuals, people with dyspeptic symptoms (nausea, vomiting, and belching) presented a low prevalence of H. pylori infection. No association between H. pylori prevalence and smoking or drinking was found. Using multivariate logistic regression analysis, annual family income and education level were the independent predictors for H. pylori infection.
Conclusion:  High prevalence of H. pylori infection was found in areas with a high risk of gastric cancer and was related to several risk factors. The underlying mechanisms need to be further investigated.     

Epidemiology of Helicobacter pylori infection in the Czech Republic

BACKGROUND: Prevalence of Helicobacter pylori infection has been estimated to range from 60 to 95% in the former communist countries of Central and Eastern Europe. The aim of this study was to evaluate H. pylori infection prevalence in a representative sample of the Czech population. The second objective was to describe difference of H. pylori prevalence between different social groups of children and adults. MATERIALS AND METHODS: A total of 2509 persons aged 5-100 years, randomly selected out of 30,012 persons of the general population, took part in the study. H. pylori infection was investigated by means of 13C-urea breath test. Breath samples were analyzed by isotope ratio mass spectrometry. Social and demographic characteristics were based on data from self-completed questionnaires. RESULTS: Using the total Czech population as a standard, we estimated the age-standardized prevalence of H. pylori in males aged 5+ years at 41.9% (95% CI 39.0%, 44.8%) and in females aged 5+ years at 41.4% (95% CI 38.6%, 44.3%) in 2001. Prevalence of H. pylori increased with age but was not related to gender. Children of mothers with basic or lower education, living in crowded accommodations, without access to running warm water, and residing in smaller towns appear to be at the highest risk. Low education and heavy smoking are most strongly associated with prevalence of H. pylori positivity in adults and adolescents. CONCLUSIONS: This is a unique study based on a representative sample of the general population in a Central European country. The overall prevalence of H. pylori is lower than previously assumed and could partly reflect a substantial recent decrease in H. pylori prevalence in the Czech Republic. Consistent with earlier studies, H. pylori infection is strongly influenced by socioeconomic conditions and childhood poverty.     

Prevalence of Helicobacter pylori Infection and Identification of Risk Factors in Rural and Urban Beijing, China

Background:  The prevalence of Helicobacter pylori is higher in developing countries such as China. The aim of this study was to investigate the prevalence of H. pylori in one rural and one urban region of Beijing, China.
Materials and Methods:  Healthy individuals in rural Pinggu and urban Haidian voluntarily participated in this study. The diagnosis of H. pylori infection was reached using the ¹³C-urea breath test. Associations between H. pylori and sex, age, living area (i.e. rural vs urban), education level, smoking, and alcohol consumption were evaluated.
Results:  Of the 1232 included subjects, 54.7% of tested individuals residing in Pinggu and 41.3% in Haidian were positive for H. pylori . In urban region, more individuals were negative for H. pylori (429 of 731), whereas in the rural region, more individuals were positive for H. pylori ( p <  .05). Univariate analysis identified geographic area and lower education and annual income as significant factors associated with H. pylori . Men in rural areas were more likely than women in rural areas to be infected, and both men and women in the rural area were more likely to be positive for H. pylori than men and women in the urban area (all p  < .05).
Conclusions:  H. pylori infection is common in both rural and urban regions of Beijing. Residing in a rural area, having a lower family income, and lower education level are significant risk factors associated with infection.     

Prevalence and risk factors of atrophic gastritis and intestinal metaplasia in a Korean population without significant gastroduodenal disease

Background and Aim: The prevalence of gastric cancer and Helicobacter pylori infection is unacceptably high in Korea. This study was performed to evaluate the prevalence of atrophic gastritis (AG) and intestinal metaplasia (IM) and to identify their risk factors with respect to H. pylori virulence factors, and environmental and host factors, in Korean population without significant gastroduodenal disease.
Methods: The study cohort consisted of 389 subjects (≥ 16 years). AG and IM were scored histologically using the Sydney classification in the antrum and body, respectively. Prevalences and bacterial factors (i.e. cagA , vacA m1, and oipA ), environmental factors (i.e. smoking and alcohol), and host factors (i.e. genetic polymorphisms of IL-1B- 511, IL-1RN , TNF-A -308, IL-10 -592, IL-10 -819, IL-10 -1082, IL-8 -251, IL-6 -572, GSTP1 , p53 codon 72, and ALDH2 ) were evaluated.
Results: Prevalences of AG in the antrum and body were 42.5% and 20.1%, and those of IM were 28.6% and 21.2%, respectively. The presences of AG and IM were significantly higher in H. pylori -positive than in the H. pylori -negative subjects. Multivariate analysis showed that the risk factors for AG were H. pylori infection, age ≥ 61 years, and cagA and vacA m1 positivity. For IM the risk factors were H. pylori infection, age ≥ 61 years, a smoking history (rather than current smoking), strong spicy food, occupation (unemployed or nonprofessional vs. professional), and the presence of IL10- 592 C/A as opposed to A/A. In addition, IL6- 572 G carrier was found to have a protective effect against IM development as compared with C/C.
Conclusion: H. pylori infection was most important risk factor of AG and IM. Bacterial factors were found to be important risk factor for AG but environmental and host factors were more important for IM.     

A "Screen-and-Treat" Approach for Helicobacter pylori Infection: A Population-Based Study in Vammala, Finland

Background:  To accelerate the decline of Helicobacter pylori infection, and to study the significance of the possible risk factors for H. pylori infection in Finland, we started a voluntary H. pylori "screen-treat-retest-and-retreat" program for all young adults at primary health care in Vammala, Finland after a pilot study in 1994 including 504 subjects aged 15–75.
Materials and Methods:  A total of 3326 aged 15–40 in 1996, and 716 aged 15 and 584 aged 45 in 1997–2000 were screened for H. pylori using serology. Helicobacter pylori positive were treated, cure was verified by serology.
Results:  The eradication rates were 93.8%, 82.2%, and 77.6% per protocol in pilot study in 1994, in subjects invited in 1996 and 1997–2000, respectively. Helicobacter pylori seroprevalence rates were calculated to have decreased from 36% to 14% in pilot study, from 12% to 4% among subjects invited in 1996, from 3% to 2% among subjects aged 15 and from 27% to 12% among subjects aged 45 in 1997–2000. An epidemiologic questionnaire in 1996 revealed that crowding in the childhood household, low education of the mother, current smoking and alcohol consumption, unfavorable housing conditions, and sick leaves due to dyspepsia were independently associated with H. pylori infection.
Conclusions:  This intervention with high participation rates resulted in a significant decline in calculated H. pylori seroprevalence rates. Although the low prevalence of H. pylori infection may limit the cost efficiency of the program, the intervention is expected to reduce the burden of H. pylori -associated diseases.     

汉中市汉台区无症状儿童幽门螺杆菌感染率的 流行病学调查

目的研究陕西省汉中地区无症状儿童幽门螺杆菌(H.pylori)感染的流行病学特点及其影响因素。方法采用酶联免疫吸附法(ELISA)检测2013年1月至2018年1月间我院328例无消化道症状儿童Hp-IgG水平情况,分析其流行病学特点,并行问卷调查研究幽门螺杆菌感染的影响因素。结果 328例无消化道症状儿童H.pylori感染率为18.90%。其中男童169例,感染率21.89%;女童159例,感染率15.72%;城市儿童137例,感染率20.44%;农村儿童191例,感染率17.80%。经Logstic回归分析,年龄3～4岁、饭前便后洗手、父母具有大学文化水平均为H.pylori感染的保护性因素;啃手指、公用洗漱杯、直系亲属胃病史均为H.pylori感染的独立危险因素,差异均有统计学意义(P0.05)。结论 H.pylori感染在儿童中较为常见,生活中不良习性与H.pylori感染密切相关。H.pylori感染相关高危因素的分析对于儿童H.pylori感染的防控具有重要临床意义。     

Risk factors for acquiring Helicobacter pylori infection in a group of Tuscan teenagers

Risk factors for acquiring Helicobacter pylori infection include hygienic, social, and environmental conditions. Some of these conditions usually change over time. We therefore investigated the existence of risk factors in a group of teenagers living in a place with the same environmental characteristics, in which hygienic and crowding conditions have not changed significantly in the last 20 years. A group of 164 students, mostly borne in 1977, attending four different schools, were examined serologically for H. pylori infection and CagA status. The importance of the risk factors for the transmission of the infection were evaluated by the chi2 test. P values <0.05 were considered significant. Twenty-two students (13.4%) were H. pylori seropositive. Students attending teachers' college and high school of arts were infected significantly more often than those attending high school (P = 0.011 and P = 0.012, respectively). Students who smoked and students whose parents had a manual job had an increased risk of acquiring the infection (P = 0.002, and P = 0.036, respectively). Crowding conditions and the presence of domestic animals were close to being statistically significant. Other factors, such as gender, number of bathrooms and bedrooms, sharing the bed with adults as a child, presence of a sexual partner, and a family history of peptic ulcer and gastric cancer, did not increase the risk of infection. The prevalence of seropositivity for CagA was similar in the various risk groups. Manual job of parents and smoking were the most important factors for acquiring H. pylori infection.     

Relation of smoking and alcohol and coffee consumption to active Helicobacter pylori infection: cross sectional study.

OBJECTIVE: To assess the relation of smoking and alcohol and coffee consumption to active Helicobacter pylori infection. DESIGN: Cross sectional study of patients attending a general practitioner. Active H pylori infection was measured by the 15C-urea breath test and detailed quantitative information on smoking and on alcohol and coffee consumption was obtained by a standardised self administered questionnaire. SETTING: One general practice in Germany. SUBJECTS: 447 patients aged 15-79 who had not had peptic ulcer disease or treatment for H pylori infection. MAIN OUTCOME MEASURES: Prevalence of H pylori infection according to smoking and alcohol and coffee consumption. RESULTS: Overall prevalence of infection was 21% (94/447). There was no significant relation between smoking and active H pylori infection. Alcohol consumption showed a negative dose-response relation and coffee consumption a positive dose-response relation with active infection. After adjustment for potential confounders, the odds ratios for patients who drank < or = 75 g and > 75 g of ethanol a week compared with non-drinkers were 0.90 (95% confidence interval 0.55 to 1.59) and 0.33 (0.16 to 0.68), respectively (P value for trend 0.005, assuming that 1 litre of beer and 0.51 of wine contain on average 50 g of ethanol in south Germany). Adjusted odds ratios for patients who drank < 3 cups and > or = 3 cups of coffee per day compared with those who did not drink coffee were 1.49 (0.71 to 3.12) and 2.49 (1.23 to 5.03), respectively (P value for trend 0.007). CONCLUSION: These results suggest a protective effect of alcohol consumption against active infection with H pylori and an opposite effect of coffee consumption.     

Infection by Helicobacter pylori and acute myocardial infarction. Do cytotoxic strains make a difference?

The classical risk factors for acute myocardial infarction (AMI) fail to explain all the epidemiological variations of the disease. Among the risk factors recently reported, several infectious agents appear to increase the risk of AMI. Helicobacter pylori (H. pylori) infection, a bacterium involved in duodenal and gastric ulcer, gastric cancer and MALT-lymphoma, seems to be strongly associated with AMI. More virulent (anti-CagA positive) strains of the bacterium are almost exclusively the causative agents of such diseases. To determine the prevalence of H. pylori infection and of virulent strains, a case-control study was conducted in a group of male patients with AMI. A group of patients consecutively admitted to the Emergency Care Unit served as controls. We studied 223 consecutive male patients, mean age 60.2 (range 40-79) years, admitted for AMI to the Coronary Care Units at Hospitals in two towns of Northern Italy, 223 age matched male patients (mean age 61.8, range 40-79 years) admitted to the Emergency Care Unit, served as control. H. pylori seroprevalence was assessed by presence of antibodies (IgG) against H. pylori and anti-CagA in circulation. Among the patients we investigated the presence of hypertension, levels of cholesterol and glucose in serum, fibrinogen in plasma and smoking habits. H. pylori infection was present in 189/223 (84.7%) of the patients and in 138/223 (61.8%) of the control population (p < 0.0001 OR 3.42 [IC 95% 2.12-5.54]). The anti-CagA antibodies were detected in 33.8% of infected patients with AMI (64/189) versus 26.8% in the control subjects (37/138) (p:0.17, OR 1.40 [IC 95% 0.84-2.33]). Classical risk factors for AMI did not differ among patients with and without H. pylori infection. Patients admitted to the Coronary Care Unit for acute myocardial infarction had a notably higher prevalence of anti-H. pylori not restricted to virulent strains, when compared to a population of patients referred to the Emergency Care Unit. The classical risk factors for coronary disease were present in the patients with AMI irrespective of H. pylori status.     

Occupational risk of tuberculosis transmission in a low incidence area

Background

To investigate the occupational risk of tuberculosis (TB) infection in a low-incidence setting, data from a prospective study of patients with culture-confirmed TB conducted in Hamburg, Germany, from 1997 to 2002 were evaluated.

Methods

M. tuberculosis isolates were genotyped by IS6110 RFLP analysis. Results of contact tracing and additional patient interviews were used for further epidemiological analyses.

Results

Out of 848 cases included in the cluster analysis, 286 (33.7%) were classified into 76 clusters comprising 2 to 39 patients. In total, two patients in the non-cluster and eight patients in the cluster group were health-care workers. Logistic regression analysis confirmed work in the health-care sector as the strongest predictor for clustering (OR 17.9). However, only two of the eight transmission links among the eight clusters involving health-care workers had been detected previously. Overall, conventional contact tracing performed before genotyping had identified only 26 (25.2%) of the 103 contact persons with the disease among the clustered cases whose transmission links were epidemiologically verified.

Conclusion

Recent transmission was found to be strongly associated with health-care work in a setting with low incidence of TB. Conventional contact tracing alone was shown to be insufficient to discover recent transmission chains. The data presented also indicate the need for establishing improved TB control strategies in health-care settings.     

Usefulness of non-invasive tests for diagnosing Helicobacter pylori infection in patients undergoing dialysis for chronic renal failure

BACKGROUND: Helicobacter pylori infection in chronic renal failure patients has been linked to peptic ulcer and gastric neoplasia after kidney transplantation. It may also contribute to the accelerated arteriosclerosis that is usual in this population. Few data are available on the usefulness of noninvasive diagnostic tests for H. pylori infection in dialyzed patients, especially regarding the new fecal antigen detection tests. The objective of this study was to determine the efficacy of a noninvasive test for H. pylori infection in patients with chronic renal failure. METHODS: Eighty-six patients were included in a cross-sectional study. Urea breath test, serology and three fecal tests--FemtoLab H. pylori (Connex, Germany), Premier Platinum HpSA (Meridian, USA) and Simple H. pylori (Operon SA, Spain) were performed. Helicobacter pylori status was determined by concordance of the tests. Sensitivity, specificity and positive and negative predictive values were calculated for each test. RESULTS: Sensitivity, specificity, positive and negative predictive values were 94%, 96%, 94% and 96% for the urea breath test; 97%, 64%, 66% and 97% for serology; 86%, 100%, 100% and 91%, for FemtoLab H. pylori; 58%, 96%, 91% and 76% for Premier Platinum HpSA and 61%, 78%, 74% and 67% for Simple H. pylori. CONCLUSIONS: The urea breath test seems to be the most reliable diagnostic method for H. pylori infection in patients with chronic renal failure. Serology has a low specificity, and the results of the fecal tests vary widely.     

Intrafamilial transmission of Helicobacter pylori among the population of endemic areas in Japan

BACKGROUND: Helicobacter pylori (H. pylori) infection is a worldwide phenomenon related to several gastrointestinal diseases. However, because many aspects concerning the route of transmission remain unclear, we performed this epidemiologic study to clarify the route of intrafamilial transmission of H. pylori. MATERIALS AND METHODS: A retrospective study was performed in three widely separate areas in Japan to investigate the prevalence of H. pylori infection. In 1993, 613 residents were tested as were 4136 in 2002, including 1447 family members of 625 families. Antibody to H. pylori (anti-H. pylori) was determined by enzyme-linked immunosorbent assay. RESULTS: In 2002, the age-adjusted anti-H. pylori prevalence in Hoshino Village (67.5%) was significantly higher than in Kasuya Town (55.0%) and in Ishigaki City (54.7%) (p < .0001, p = .0039, respectively). The age-adjusted anti-H. pylori prevalence of Ishigaki City significantly decreased from 1993 (68.4%) to 2002 (52.5%), showing an age cohort effect. However, the prevalence did not significantly differ in children aged 0-6 years of Ishigaki City between 1993 (9.6%) and 2002 (10.3%). A familial analysis in 2002 demonstrated that the prevalence of anti-H. pylori was significantly higher in children with anti-H. pylori-positive (21.6%, 22 of 102) than with -negative mothers (3.2%, 3 of 95) (p < .0001, by Mantel-Haenszel test), whereas there was no significant difference between children with anti-H. pylori-positive and -negative fathers. Moreover, the prevalence was significantly higher in wives with anti-H. pylori-positive (64.0%, 208 of 325) than with -negative husbands (46.5%, 80 of 172) (p = .0071, by Mantel-Haenszel test) and in husbands with anti-H. pylori-positive (72.2%, 208 of 288) than with -negative wives (56.0%, 117 of 209) (p = .0106, by Mantel-Haenszel test). CONCLUSIONS: In the last decade, H. pylori infection decreased in the general population of Japan by improvement of general hygiene conditions, but did not differ in young children, most likely because of mother-to-child transmission.     

Epidemiology of Helicobacter pylori Infection in Asymptomatic Children: A Prospective Population-Based Study from the Czech Republic. Application of a Monoclonal-Based Antigen-in-Stool Enzyme Immunoassay

Background:  Acquisition of Helicobacter pylori occurs mainly in childhood and is significantly influenced by geographical variations. The aim of this study is to evaluate the prevalence of H. pylori infection in a population-based sample of asymptomatic children in the Czech Republic. Furthermore, this study aims to identify potential risk factors associated with this infection.
Materials and Methods:  A prospective, cross-sectional, population-based study was undertaken in 1545 asymptomatic Czech children (aged 0–15 years; male 49.3%). Active H. pylori infection was diagnosed by monoclonal antibody-based antigen-in-stool enzyme immunoassay. Socio-demographic details of each subject were analyzed using a self-administered standardized questionnaire. Multiple regression analysis was performed.
Results:  Overall, 7.1% of asymptomatic children were diagnosed with H. pylori infection. Of the infected children, 5.8% lived in the general population. A positive association was found with increasing age, although not with gender. Independent risk factors associated with H. pylori infection in our pediatric population were: the number of children in a household (odds ratio [OR] 4.26; confidence interval [CI] 1.91–9.80); lack of formal education of fathers (OR 0.23; CI 0.18–0.64) and institutionalized children (OR 6.33; CI 2.25–26.50).
Conclusions:  This study of a large cohort of children demonstrated that, independent of gender, H. pylori infection in the Czech Republic is among the lowest reported in Europe. Socioeconomically disadvantaged children, unfortunately, are still at risk of harboring this potentially preventable infection in this low-prevalence region.     

A Population-Based Epidemiologic Study of Helicobacter Pylori Infection and its Association with Systemic Inflammation

Background:  Infection with Helicobacter pylori is associated with a variety of non-gastrointestinal sequelae. These may be mediated by an increase in systemic inflammation. We assessed if serologic evidence of infection with H. pylori is associated with increased serum C-reactive protein (CRP) levels.
Methods:  The study design consisted of a randomly selected, cross-sectional population-based study of 2633 individuals phenotyped in 1991, of whom 2361 participants provided serum samples to permit measurement of H. pylori 's serologic status and CRP levels.
Results:  Male gender (odds ratio (OR): 1.65; 95% confidence interval (CI): 1.23–2.21), age (OR per year: 1.05; 95% CI: 1.04–1.06), height (OR per meter: 0.05; 95% CI: 0.01–0.24), current smoking habit (compared with never smokers, OR: 1.46; 95% CI: 1.13–1.88), and less affluent socioeconomic status were associated with increased odds of being seropositive for H. pylori . Helicobacter pylori infection was associated with increased risk of having an elevated serum CRP (above 3 mg/L) after adjustment for gender, age, height, smoking status, and socioeconomic status (OR: 1.32; 95% CI: 1.05–1.67). Similar associations were seen using a threshold for elevated serum CRP of greater than 1 mg/L.
Conclusions:  Our data suggest that infection with H. pylori is associated with increased systemic inflammation. This suggests one potential mechanism to explain the extra-gastrointestinal conditions associated with H. pylori infection.     

Helicobacter pylori in Japanese river water and its prevalence in Japanese children

AIMS: The major transmission route of Helicobacter pylori remains unclear. In this study, we examined H. pylori in the environmental waters in Japan. METHODS AND RESULTS: A total of 24 water samples were collected from the upper, middle and downstream reaches of four Japanese rivers. Helicobacter pylori-specific DNA was examined using nested PCR. In addition, 224 children who lived near one river were studied by the stool antigen test for H. pylori prevalence. Helicobacter pylori DNA was detected in the water from the middle and downstream reaches of all four rivers, but not in the upper reaches. Helicobacter pylori was not found in cultured water samples with positive PCR results. Helicobacter pylori prevalence in the children examined was 9.8% for those living near the middle reaches and 23.8% nearby downstream, both of which were higher than the value in an area distant from the river (0%) (both, P < 0.01). CONCLUSIONS: Difference in H. pylori prevalence in the children may be related to the presence of H. pylori in the river. The results of this study showed that H. pylori DNA is frequently present in river water from the middle and downstream reaches in which the human biosphere is embedded. SIGNIFICANCE AND IMPACT OF THE STUDY: It is suggested that river water in the natural environment could be a risk factor for H. pylori transmission.     

The infection by Helicobacter pylori strains expressing CagA is highly prevalent in women with autoimmune thyroid disorders.

H. pylori infection is putatively associated with extra-digestive disorders and may also play a role in the development of autoimmune thyroid diseases (ATD). It was recently found that monoclonal antibodies to an H. pylori strain with cagA-positivity reacted with follicular cells of the thyroid gland, and that an H. pylori organism possessing the cag pathogenicity island carried a gene encoding for an endogenous peroxidase. The aims of this study was (1); To ascertain whether the infection by strains endowed with an increased inflammatory potential (those expressing CagA) could further enhance the risk of developing ATD (2); To verify the possible existence of an immune cross-reactivity between autoantibodies to peroxidase and thyroglobulin and H. pylori antigens (3). To establish whether thyroid colloid antigens could cross-react with an anti-H. pylori serum. The study was partly designed retrospectively. We examined 41 consecutive women with ATD, and, as a control, 33 consecutive age- and socio-economic class-matched women without autoimmune thyroid disorders, living in the same area as patients, occurred at the same institution in the same period (six months). Both patients and controls were examined serologically for H. pylori infection and CagA status by Western blotting. Some serum samples were absorbed with H. pylori to determine whether the antibody levels decreased. Colloid proteins were resolved electrophoretically and matched with a hyperimmune serum raised in rabbits against a CagA-positive H. pylori. Thirty-two patients (78.0%) tested seropositive for H. pylori infection, vs. 16 controls (48.4%) (P = 0.008, OR = 3.78, RR = 1.61). The prevalence of anti-CagA antibodies was 71.8% in infected patients, and 50% in infected controls (P = 0.161, n.s.). The overall prevalence of infection by CagA-positive H. pylori was significantly higher in patients with ATD (23/41, or 56.0%) than that in controls (8/33, or 24.2%) (P = 0.006, OR = 3.99, RR = 2.31). The other tests gave negative or inexplicable results. In conclusion: CagA-positive H. pylori infection increases the risk of ATD development.     

Seroprevalence of Helicobacter pylori infection among schoolchildren and teachers in Taiwan

BACKGROUND: Helicobacter pylori are associated with chronic antral gastritis that is related to duodenal ulcer, gastric ulcer, and probably gastric adenocarcinoma. Infection of H. pylori during childhood is considered an important risk factor for gastric carcinoma in adult life. MATERIALS AND METHODS: To examine the epidemiologic characteristics of H. pylori infection among schoolchildren in central Taiwan, a community-based survey was carried out using stratified sampling in 10 elementary schools and three junior high schools including students and theirs teachers. Serum specimens of 1950 healthy schoolchildren (aged 9-15 years old) and 253 teachers who were randomly sampled were screened for the H. pylori antibodies by enzyme-linked immunosorbent assay. Statistical analysis was performed by using the SPSS for Windows statistical software system. RESULTS: A total of 332 subjects were H. pylori antibodies positive, giving an overall prevalence of 15.1%. The age-specific seropositive rates were 11.0% in 9-12 years age group, 12.3% in 13-15 years age group, and 45.1% in the teacher group. The older the age, the higher the seroprevalence (OR = 11.53; 95% CI = 6.73-19.74; p < .001 for children vs. teachers). There was no difference in the seroprevalence of H. pylori infection by gender, ethnicity, geographical area, socioeconomic level, parental education, sibship size, family members, and source of drinking water. CONCLUSION: The teachers had a much higher prevalence of H. pylori antibodies. The finding suggests that these teachers (adults) might be infected in their early childhood and implies that the poor environmental and hygienic conditions might be responsible for it. It seemed that poor water supply system, sewage disposal, and other environmental hygiene in adult might play some roles in H. pylori infection in Taiwan (before early 1980s).     

Problem of distinguishing false-positive tests from acute or transient Helicobacter pylori infections

BACKGROUND: Reliable detection of acute Helicobacter pylori infections remains problematic. The high prevalence of false-positive non-invasive tests in low H. pylori prevalence populations makes identification of acute and transient infections difficult. METHODS: We explored the use of serum pepsinogens (PG) for diagnosis of acute infection in patients following H. pylori challenge such that the onset of the infection was known. We then compared those findings to a group of children with presumed acute infections defined as a positive urea breath test (UBT) and negative IgG serology. RESULTS: We examined the pattern and calculated cut-off values of PG levels in 18 adult volunteers with known acute H. pylori infection. We then compared the results with sera from nine symptomatic children with presumed acute H. pylori infection and a matched control group of nine children who did not meet criteria for acute H. pylori infection. In acute infection, both PGI and II levels increased following H. pylori infection reaching a peak by 2 weeks post-infection. The frequency of a positive test defined as a value > mean +2 SD was 17, 71, and 94% at week 1, 2, and 4 post-infection, respectively. Only one child with presumed acute H. pylori infection had an elevated serum PGI and one had an elevated PGII. Five of the children had follow-up UBTs and four were negative consistent with the diagnosis of false-positive UBT. H. pylori infection was confirmed in the child with an elevated PGI level. CONCLUSIONS: These data suggest that a single positive noninvasive test in populations of low prevalence is most likely a false-positive result. This suggests that a single positive test requires confirmation preferably using a test that measures a different parameter (e.g., UBT confirmed by stool antigen test). It appears that most "transient"H. pylori infections are diagnosed on the basis of false-positive tests. PG levels are possible candidates as the confirmatory test.